1. 编辑距离（困难）

地址: https://leetcode-cn.com/problems/edit-distance/
2021/12/
解法一：自顶向下
做题反思：

java">

解法二：自底向上
2021/12/27
做题反思：

java">class Solution {
    public int minDistance(String word1, String word2) {
        int m = word1.length(), n = word2.length();
        int[][] dp = new int[m + 1][n + 1];

        for (int i = 1; i <= m; i++) {
            dp[i][0] = i;
        }
        for (int j = 1; j <= n; j++) {
            dp[0][j] = j;
        }

        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                if (word1.charAt(i - 1) == word2.charAt(j - 1)) {
                    dp[i][j] = dp[i - 1][j - 1];
                } else {
                    dp[i][j] = min(
                        dp[i][j - 1] + 1,
                        dp[i - 1][j] + 1,
                        dp[i - 1][j - 1] + 1);
                }
            }
        }
        
        return dp[m][n];
    }

    int min(int a, int b, int c) {
        return Math.min(a, Math.min(b, c));
    }
}